1. Field of the Invention
The present invention relates to control devices for switching equipment from an operating state to a non-operating condition. In particular, the invention relates to a control device for controlling agricultural sprayers.
2. Description of the Prior Art
Need for the present control device arises from recognition of conservation problems associated with ground operated agricultural sprayers. These agricultural sprayers are used for depositing onto crops chemicals that increase yields and control crop destroying pests. Many efforts are being made to decrease chemical waste. These efforts include development of precision spray systems that can greatly decrease the quantity of spray materials used on crops without compromising effectiveness, and can reduce the potential pollution arising from off-target deposition. Sensor-controlled precision spray systems are designed to tailor chemical delivery. Two basic types of systems available for certain types of crops use ultrasonic devices or lasers. Many precision systems include onboard computers that can be used to program basic sprayer functions and monitor savings from use of the sensor-controlled systems. Monetary savings are recognized from conservation of spray by turning off nozzles in gaps or when crops do not meet height specifications or the like.
Many efforts are also being made to reduce off-target spray deposition. Besides decreasing production costs, reducing off-target spray application offers the potential of substantially reducing pollution of surface water with spray materials. Off-target spraying may result from application error by not shutting off the boom at the end of a field or when the rig stops. Failure to turn off the boom spraying chemical may result in overspraying a target area or spraying a non-target area. Such fail often causes wasted chemicals, off-target damage, on target damage from over application, higher costs and negative environmental impact to water and air quality.
Further, over spraying may result in increased spray drift, which can cause injury to humans, nearby crops, livestock, and wildlife and costs money not only for waste but for restitution for damaged crops. About ¼ of insurance payouts for misapplication of chemicals is caused by equipment effectiveness and another ⅓ is caused by drift. Thus, a need exists for continued improvement of spray equipment to help applicators keep the application on target.
Commercial agricultural sprayers include an inline valve that controls the release of chemical through a boom having several spray nozzles. Often, the operator manually controls the valve and is responsible for starting and stopping the sprayer. For instance, the operator starts the sprayer when beginning a new row and shuts off the sprayer when traveling to the end of a row or shutting down. Unfortunately, operators make errors or become complacent and forget to start the sprayer or neglect shutting the sprayer off at the desired time. These operator errors cause undesirable over-spray or under-spray. Eliminating such under-spray or over-spray situations by eliminating these operator errors will profit the industry and the environment.
Sprayers generally are supported by ground wheels and travel thereby. The ground wheels rotate in a normal fashion about a rotary shaft. When the sprayer is not moving or changing direction, the ground wheels stop or slow, and it is advantageous for disposition of spray from the sprayer's booms to cease. Further, the sprayer is generally raised from the ground at the end of a row of crop or between use. The ground wheels of the sprayer are disengaged when the sprayer is raised and the ground wheels are not in contact with the ground. It would be desirable to provide a method of automating the shut-off of the sprayer in accordance with the travel of the sprayer or the raising of the sprayer.
Various computerized control systems for sprayers are known for monitoring sprayer performance. For instance, the Deere & Company produces the SPRAYSTAR™ vehicle and rate control system that constantly monitors sprayer performance. Such monitoring systems assist in controlling spray disposition rates and response times. Features include programmable application rates, pressure control, volume counters, and other measures of sprayer performance. However, these monitoring systems do not provide for mechanically automated safety shut-off of the disposition of spray in accordance with the travel of the sprayer, and the precision spray systems discussed above are not suited to controlling the spray system in accordance with the travel of the underlying machine.